This invention is related to copending, commonly assigned U.S. application Ser. No. 502,726. filed Apr. 2, 1990. It is also related to copending, commonly assigned U.S. application Ser. No. 771,016, Szajewski, et al. entitled Photographic Silver Halide Material with Improved Color Saturation filed concurrently.
This invention relates to a photographic element containing a barrier layer. The invention more specifically relates to a barrier layer which will reflect a development inhibitor or precursor released in another layer in the photographic element to prevent the migration of the development inhibitor.
It is known in the photographic art to use development inhibitor releasing compounds in photographic elements to selectively control the development of silver halide emulsion layers. The use of these compounds can result in desirable improvements in sensitometry and image structure by reducing contrast and introducing intralayer and interlayer development effects. The release of these inhibitors upon development can reduce the granularity and enhance the sharpness of the image. The use of development inhibitor releasing couplers which react with the oxidation product of a color developing agent to release a development inhibiting fragment is described in U.S. Pat. Nos. 4,782,012, 4,477,563 and 4,248,962.
It is well known that excessive migration of a development inhibitor from the emulsion layer from which it is released can detrimentally affect the processing of other silver halide emulsion layers in the same photographic element or in subsequently processed photographic elements. For example, intralayer migration of a released development inhibitor can provide improved sharpness and reduced contrast and granularity, at the same time, interlayer migration of the development inhibitor may provide more interimage effect than is desired.
Another serious problem involving the wandering of development inhibitors is that they can diffuse into the developing solution from the photographic element and undesirably "season" the developing solution. Thus, the concentration of development inhibitor is built up in the developing solution, and the sensitometry of subsequently processed film is affected in a non-imagewise manner.
It is known to include in photographic materials scavenger layers for the released development inhibitors to help prevent unwanted interlayer diffusion. Such scavenger layers include the use of Lippmann emulsions in layers above, between or under image forming emulsion layers to inhibit development inhibitors from migrating either between layers or from the element to the developing solution. Other inhibitor adsorbing layers are described in U.S. Pat. Nos. 3,984,245 and 4,055,429. The use of fine grain silver halide layers, however, has been found to sometimes alter the sensitometry of the image-forming layers adjacent thereto. The use of interlayer formulations which adsorb the development inhibitor may require the use of a higher concentration of the inhibitor releasing compound to provide the desired intralayer effect.
U.S. Pat. No. 4,504,569 suggests the use of a N-alkyl substituted acrylamide with a defined solubility parameter as a temporary barrier layer between reactants such as developing solutions and development restrainers. The polymers described however, are timing layers and are used in color image transfer film units. Such timing layers are not used in photographic materials intended for traditional processing because they will prevent the diffusion of processing solutions until the timing layer breaks down thus unnecessarily slowing down the processing.
The need exists, therefore, for an improved means of allowing the enhancement of intralayer effects achieved through the use of development inhibitors while at the same time controlling undesired interlayer effects.